Abstract: An envelope feedforward technique is described that provides efficient, variable-power, linear amplification of an input signal. An input signal having phase and amplitude components is separated (decomposed) into an FM portion and an envelope portion. The FM portion contains the high frequency phase and frequency information from the input signal. The envelope portion contains the low frequency amplitude information from the input signal. An envelope combiner uses the envelope signal to amplitude-modulate the FM signal to produce an output signal. Spectral regrowth of the output signal is reduced by adjusting the relative time delays in the signal path of the envelope signal and the FM signal such that the FM signal and the envelope signal arrive at the envelope combiner at the same time. The envelope feedforward technique may be used to increase battery life in a handheld mobile RF unit such as a cellular telephone.